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' ATTORNEYS Dec. 26, 19'67" SAMPLE APPLICATOR USED IN-ELECTR'OPHORESIs United States Patent O 3,360,454 SAMPLE APPLICATOR USED IN ELECTROPHQRESIS Otto H. Sahmel, Rochester, N.Y., assignor to Bausch & Lomb Incorporated, Rochester, N.Y., a corporation of New York Filed Apr. 2, 1965, Ser. No. 445,072 Claims. (Cl. Zim- 299) This invention relates to electrophoresis and more particularly to a sample applicator for depositing the test sample on the electrophoretic migration medium.

The process of electrophoresis requires a migration medium upon which the test sample is deposited. The sample is migrated in an electric eld and the various fractions of the test sample migrate in proportion to their electrical charge, mobility, and other conditions associated with the process. It is important that the test sample be accurately positioned on, or in the migration medium in order that an accurate reading be achieved. Accordingly, this invention provides a test sample applicator which accurately deposits the sample on the electrophoretic medium and the applicator can be easily removed with a minimum of tearing and deformation of the gel surface.

It is an object of this invention to provide a sample applicator for depositing a test sample on the surface of a medium or in the medium.

It is a further object of this invention to provide a test sample applicator which deposits a test sample on a straight line across the surface of an electrophoretic medium and which permits the removal of the central bar on the applicator while end pieces of the applicator remain liXed to the migration tank.

The objects of this invention are accomplished by providing a central bar which carries the two end pieces upon which a string is taut in a straight line. The taut string provides a straight line for carrying the test sample which can be applied on the surface or in an electrophoretic medium. The central bar can then be removed while the end pieces are retained within a receptacle portion on a migration tank supporting the migration medium. 'Ihe string may be released subsequent to migration of the test sample without appreciable deformation ofthe electrophoretic mediumsurface.

The preferred embodiment of this invention is described in the subsequent paragraphs and illustrated in the attached drawings.

FIG. 1 illustrates the applicator mounted on a tank supporting the electrophoretic medium and a phantom view of the central bar removed.

FIG. 2 illustrates a plan view of the applicator.

FIG. 3 illustrates a bottom View of the applicator.

FIG. 4 illustrates the applicator just above its position on the migration tank.

FIG. 5 is a fragmentary cross section view taken on the axis of the left end of the applicator shown in FIG. 2.

FIG. 6 is an enlarged View of a modification of a spring.

Referring to the drawings FIG. l illustrates a tank 1 which supports the applicator. The table 4 is shown in FIG. 4 supported intermediate the butter solution charnbers 2 and 3 in the tank 1. The table 4 supports an electrophoretic medium 5. The buffer solutions 6 and 7 are adapted for connection to the electrical circuit which applies a positive and negative charge to the buffer solutions respectively. The conductors 8 and 9 electrically connect the electrophoretic medium 5 to the two butler solutions end pieces 12 and 13. A latch 14 is received within thel notches 15 of the end piece 12. The latch 16 is received 3,360,454 Patented Dec. 26, 1967 within a similar notch 17 of the end piece 13. The latches 14 and 16 are spring loaded by the coil spring 18 positioned intermediate the latches. A screw 19 attaches the finger rest 20 to the latch 14 and the screw 21 attaches the linger rest 22 to the latch 16. A depending portion 23 extends downwardly from the end piece 12 and is received within the receptacle portion 35 in the sides of the tank 1. A similar depending portion 24 is received in a similar receptacle portion on the opposite side of the tank 1.

A coil spring 25 is received within an annular opening 26 which is formed on the end of the slot 27. The coil spring is of slightly larger diameter than the opening 26 and accordingly holds the string 28 in position. A leaf spring 30 may also be used in place of the coil spring 25 i for fastening the end of the string. The opposite end of the string 28 is bonded to the ball 29 as shown in FIG. 5.

The central bar 11 in phantom is shown removed from the end pieces 12 and 13 in FIG. 1. The end pieces are retained -in their respective receptacle portion on the sides of the tank 1. The string is retained in the end pieces taut along the surface of the electrophoretic medium 5 by the end pieces 12 and 13. The only part of the applicator remaining within the migration area over the table 4 is the string 28.

The bottom side of the applicator is shown in FIG. 3. Pour spring clips 31, 32, 33 and 34 are fastened to the side of the central bar 11. These clips retain the end pieces in engagement with the central bar 11 so long as the latches 14 and 16 remain in their respective notches 15 and 17.

Pressing of the linger rest 20 and 22 together shortens the spring 18 and withdraws the latches 14 and 16 from their respective notches 15 and 17. This permits the removal of the central bar 11 from the end pieces 12 and 13. The end pieces 12 and 13 each have a depending portion 23 and 24 respectively which is received within the receptacle portions 35 and 36 respectively of the tank 1. The shoulders formed by the notches in the sides of the tank 1 engage the lateral surfaces of the end pieces 12 and 13. In this position the central bar is no longer needed for rigidity in maintaining the spaced relationship of the end pieces 11 and 12.

The string is preferably made of an absorbent material. Sections on the string are then preferably coated with a sealing substance which prevents the migration of the sample through the string to adjacent samples. A string of this type may be used to deposit as many samples as there are areas intermediate the coated sections. An absorbent string is preferable because the sample can be readily applied to the string.

The device operates in the following manner. A spring having a ball bonded to its end is slipped into the slot 38 and pulled across the slotted linger 39. The string is pulled tight against the finger 40 on the end piece 13 and pulled into the slot 27 and fastened by the Irm engagement of the spring 25 expanding against the inner periphery of the annular opening receiving the spring 26.

The applicator is then pressed into position on the tank 1 and the depending portions 23 Iand 24 .are received Within their respective receptacle portion formed in the tank 1. In this position the string engages the upper surface of the electrophoretic medium 5.

When the -central bar 11 is to be removed the two finger rests 20 and 22 are pressed together to withdraw the latches14 and 16 from their yrespective notches 15 and 17. The central bar 11 can be lifted out of position from the end pieces 12 and 13.

The migration of the test sample is then performed through the electrophoresis apparatus. The string 28 can then be removed by releasing the string 28 from spring 25 and drawing the string laterally .across the surface Krnight fall within the scope of the invention `as described in. the following claims.

I claim:

1. A sample applicator for applying a test sample to the migration medium on a table of .an electrophoretic tank comprising, tWo end pieces, a central bar providing rigidity to the applicator having a latching means attachin g vsaid two end pieces to said lcentnal bar, means for engaging a string to each olf said two end pieces in a taut position intermediate said end-pieces inclu'ding a string fastener on each of said end pieces for engaging said string to the respective end piece, means on said bar for releasingrsaid latching means upon positioning of the end pieces in the desired position on an electrophoretic tank.

2. A sample applicator for applying a test sample to the migration medium Ion a table of an electrophoretic tank having receptacle portions comprising, end pieces adapted for reception in receptacle portions on the side of a migration tank, a center bar retaining the end pieces Iin fixed relation relative to each other, means for fastening at least one string between each of the 'end pieces and held taut between said end pieces, latching means on said central bar for releasing said end pieces upon reception of said end pieces in the receptacle means of said migration tank to thereby hold the end pieces in ixed position relative to each other.

3. A sample applicator for applying a test sample to a migration medium on a migration table, a migration tank including said migration table yand having receptacle means on its Ilateral edges, said .applicator comprising, two end pieces having portions mating the receptacle means Iin -said migration tank, la central bar detachably engaging said end pieces, means on each of said end pieces for fastening a string in a taut position, said string being used to `apply at least one sample to the migration table, a latch on said central bar having means for releasing said end pieces from said central bar upon reception of the end pieces in the receptacle means of said migration tank.

4. A sample applicator for applying a test sample to a migration medium on a migration table, a migration tank including the migration table and lincluding receptacle means on opposing sides yof the migration table, said applicator including a central bar having a latch on both ends, two end pieces each having depending portions extending downwardly on the inner and outer surfaces of the edge of said tank and for reception in said receptacle means, means for fastening a string to engage each of said end pieces and for retaining the string taut across the bottom of said applicator, means operating said latches on said cent-ral bar for detaching `said end pieces from said central lbar when said end pieces are inserted in thefreceptacle means of said migration tank.

5. A sample applicator for Iapplying a test sample to a migration medium on a table of an electrophoretic tank Icomprising two end pieces, a central bar having a latching means for attachment of said bar to said end pieces to provide rigidity to the applicator, means for fastening an absorbent string in a taut position to each olf said two end pieces, said string having sealing means .alternately positioned on sections to prevent absorbence of the sample across the sealed sections of said string, means for releasing said end pieces by said latching means upon positioning of the end pieces in the desired position on an electrophoretic tank.

References Cited UNITED STATES PATENTS 3,114,692 12/1963 MacDonell 204-299 3,317,418 5/ 1967 ZeC 204-299 OTHER REFERENCES Smithies: An Improved Procedure for Starchgel Electrophoresis: Further Variations in the Serum Proteins of Normal Individuals, in Journal of Biochemistry, volume 7l, 1959, pages 585 to 587.

ROBERT K. MIHALEK, Primary Examiner.

E. ZAGARELLA, Assistant Examiner. 

1. A SAMPLE APPLICATOR FOR APPLYING A TEST SAMPLE TO THE MIGRATION MEDIUM ON A TABLE OF AN ELECTROPHORETIC TANK COMPRISING, TWO END PIECES, A CENTAL BAR PROVIDING RIGIDITY TO THE APPLICATOR HAVING A LATCHING MEANS ATACHING SAID TWO END PIECES TO SAID CENTRAL BAR, MEANS FOR ENGAGING A STRING TO EACH OF SAID TWO END PIECES IN A TAUT POSITION INTERMEDIATE SAID END-PIECES INCLUDING A STRING FASTENER ON EACH OF SAID END PIECES FOR ENGAGING SAID STRING TO THE RESPECTIVE END PIECE, MEANS ON SAID BAR FOR RELEASING SAID LATCHING MEANS UPN POSITIONING OF THE END PIECES IN THE DESIRED POSTION ON AN ELECTROPHORETIC TANK. 